Nerve growth factor and substance P: expression in a rat model of diabetic bladder

To evaluate the gene and protein expression of nerve growth factor (NGF) and substance P (SP) in the bladder 8 weeks after diabetes induction and investigate the pathogenesis of diabetic cystopathy.

Thirty Wistar rats were divided into three groups: control (n = 10), streptozotocin-induced diabetic group (n = 10) and Pygeum africanum (P. africanum) group (n = 10; diabetic rats were given P. africanum (100 mg/kg/day)). Eight weeks later, the bladders were dissected. We measured the expression of NGF and SP in the bladders using RT-PCR, ELISA and immunohistochemistry.

We found a significantly reduced expression of NGF in the bladders from the diabetic group compared with the control. Immunohistochemical studies showed a statistically significant reduction of SP in the bladders from the diabetic group compared with the control (P < 0.05). Expression of NGF was greatly increased in the P. africanum group compared with that of the diabetic group. Immunohistochemical studies showed an increased level of SP in the bladders from the P. africanum group compared with the control (P < 0.05).

Our findings indicated that the decrease in NGF and SP may be a contributory factor in diabetic cystopathy. In addition, P. africanum could significantly upregulate the expression of NGF and SP in diabetic rats.